<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>矩形</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }
    </style>
</head>

<body>

    <svg width="800" height="800" xmlns="http://www/w3.org/2000/svg" version="1.1">
        <!-- 
            cx cy 定义圆点的x和y的坐标,如果省略不写则默认为(0,0)
            r: 定义圆的半径
            stroke-width: 边框的宽度
         -->
        <circle cx="100" cy="100" r="40" stroke="black" stroke-width="8" fill="red" />
    </svg>
</body>

</html>